In molding machines, including, for example, those for forming and shaping blow molded components, problems frequently occur when heated preforms (e.g., pre-blown/pre-molded pieces of material) are transferred from the heating device by means of a transfer star or similar rotational transport device, in which the mutual spacing of the preforms is modified, to the also circulating blow wheel. Due to the spacing change the preforms undergo an acceleration which bends the soft heated material because the forces acting on the preforms, in particular centrifugal force, and therefore the preforms are inserted in the blowing mold machine as “bananas”. Thus upon longitudinal stretching of a preform by the stretching rods, it is not always guaranteed that the stretching rods will stretch the preform uniformly to its base and so called “off-centers” can occur. These are containers in which the injection point is not arranged in the center of the container, but to one side of the container. This has detrimental effects on the strength of the container base so that, for example, depending on angle position, a container can have different wall thicknesses or can bulge from pressurized contents such as, for example, CO2-containing beverages.
Additionally, in blowing machines, a preform is typically exposed to various forces, including centrifugal forces which can bend or deform the preform. Particularly in rotating blowing machines, the opening where the transfer of performs/containers to and from the blowing machine occurs is normally outward from the axis about which the blowing machine sides are opened while the longitudinal axis of a preform is typically parallel to the rotary axis of the rotating blowing machine, and by rotation of the blowing carousel, centrifugal forces occur which must be countered upon opening and closing the blowing machine and transfer of the preform or container.
U.S. Pat. No. 4,355,968, published on Oct. 26, 1982, German Patent Publication No. DE 29708808 U1, published on Jul. 23, 1998, and U.S. Pat. No. 5,116,217, published on Oct. 26, 1982, each generally propose an apparatus according to which a preform is moved out of one vertically oriented position into a vertical position rotated through 180°. This can be done to reduce the thermal load on the thread on a preform and thus avoid undesirable heating of the threaded section of a preform.
French Patent Publication No. FR 2917290, published on Dec. 19, 2008, discloses a device according to which preforms fitted with a holding device can be rotated in a defined manner.